Ok, here's the info I have.
Teleflex # 52320S009 3/8" NPT 120-240 degrees.
The original sender is left in place. Remove water hose nipple where it leaves the thermostat housing and install a threaded nipple and "T" (3/8). Reattach the water hose nipple into the end of the "T" and install the new sender to the "T".
This one is pretty easy.
Teleflex # IA15001 1/8" NPT
Remove the original sender which is 1/8" x 28 BSP
And now for the part that will drive you nuts looking for it.
A 1/8" BSP to 1/8" NPT converter
I managed to find one at a local hot rod shop for imported cars. This might be the only place where you can find these as I looked and looked for a long time before I came across this place.
I attached the converter to the middle of a 1/8" NPT "T" with the original sender and the new sender on either end. Its a tight fit, but no problems after 2 years. Take your time with the oil sender section, it can be tricky.
I used a complete set of matching gauges from Teleflex to complete the setup with the idiot lights and buzzer still functioning on the Yanmar engine
panel. Here there are being test fitted: